Research On Seismic Performance Of Blind-side Bolted Beam-column Steel Frame Connection

In the steel structure system,most of the current domestic and foreign scholars’ researches focus on the connection of H-shaped columns and beams,but the H-shaped steel columns are subjected to uneven forces due to the large difference in the moment of inertia of the strong and weak axes of the cross-section,so the use of square steel pipe columns can have It is beneficial to maintain the stability of the structure and effectively improve the bearing capacity and lateral stiffness of the structure.However,the tightness of the section of the square steel pipe column makes the design and construction of the square steel pipe column-H-beam joint difficult.The blind-side bolted connection has better mechanical performance.Therefore,this paper starts with the research on the mechanical performance of the T-shaped connector in the blind high-strength bolted beam-column joint,and studies the influence of different parameters on the mechanical performance of the T-shaped connector,and then follows the research law from local to overall.The steel frame model of this connection form is established and the seismic performance test is carried out to provide reference for the practical engineering application of the new semi-rigid connection steel frame.The main research contents are as follows:(1)Carry out six groups of 11 blind high-strength bolts to connect T-pieces with mechanical performance test research,respectively changing the thickness of the T-piece web and flange,comparing the failure mode and stress of blind high-strength bolts and ordinary high-strength bolts.Mechanical properties,considering the shear of T-shaped pieces and the influence of shear force,adopting the form of different holes and welding stiffeners in the column,to study the failure characteristics and stress mechanism of this type of joint.The test results show that under the same conditions,increasing the thickness of the web and flange of the T-shaped piece can effectively improve the tensile bearing capacity of the T-shaped piece.It is the first to be damaged,so a moderate size of T-shaped parts should be selected in the frame test;the test is carried out using blind high-strength bolts and ordinary high-strength bolts.The T-piece will not affect the bearing capacity of the T-specimen.However,considering the shearing effect and shearing force of the T-shaped piece,the bearing capacity of the T-shaped piece will be reduced;the use of different holes can improve the influence of premature extrusion and deformation of the blind high-strength bolt due to the excessively large diameter of the bolt,and the welding in the column is strengthened.Ribs can enhance the stiffness of the column and reduce the plastic deformation of the specimen.(2)On the basis of studying the mechanical performance of the blind high-strength bolt-T-shaped connection,select the appropriate size of the T-shaped part to study the mechanical performance of the beam-column connection of the blind high-strength bolted steel frame.A horizontal low-cycle reciprocating load is applied to the designed steel frame to study the failure characteristics,stress mechanism,plastic strain development law,hysteretic characteristics,stiffness degradation,ductility and energy dissipation capacity of the steel frame,as well as the relative rotation angle of beams and columns in the frame.The test results show that: the hysteresis curve of the frame is relatively full,there is no obvious pinching phenomenon,and the hysteretic performance is good;the horizontal bearing capacity of the frame is high,and the lateral stiffness is relatively large,and the stiffness degradation is relatively stable;At the same time,it has good energy dissipation capacity and ductility,and the overall seismic performance of the frame is good.(3)Referring to the test piece of blind high-strength bolted T-piece joint and the geometric dimensions of the steel frame connected by this joint,a three-dimensional solid model is established by numerical analysis software(ABAQUS),and nonlinear numerical simulation analysis is performed on it.The failure mode,plastic development,load-displacement curve,etc.of the test and the finite element model are compared and analyzed,and the fitting effect is good with the test,which verifies the correctness of the finite element modeling method used in this paper.47 figures,12 tables,and 96 references.